EUCIILANID^E. 93 



striate. An eye- spot which appears to be unconnected with the brain, is situate nearer 

 the pectoral than the dorsal side. 



I found this species in 1849 in ponds around London, and have seen it often since. 

 It has sometimes occurred so large that even with the naked eye I have had no difficulty 

 in distinguishing thft head from the foot. P.H.G.] 



I once found among a number of specimens of E. deflexa a perfectly empty lorica, 

 belonging to this species, and fortunately standing up vertically, so that it turned 

 round and round on its pointed end, as on a pivot (PI. xxiv. fig. Ic). I was thus 

 enabled to see with the utmost distinctness that it was closed everyivherc except a large 

 opening in front, where the head had protruded, and a small one behind, that had given 

 a passage to the foot. The ventral plate (fig. Ic ; v], as I term it the ventral membrane 

 as Mr. Gosse considers it had no flange, but seemed to me quite as stout and stiff as 

 (not to say stiffer than) the other ventral parts of the lorica. Whatever it was, whether 

 chitinous plate or membrane, it had remained with the rest of the lorica while the softer 

 tissues of the animal had disappeared. 



Length, ^ to $ inch ; breadth, T ^ inch. Habitat. Pools and lakes (P.H.G. : 

 C.T.H.) : widespread. 



E. PYEIFOEMIS, Gosse. 

 (PI. XXIII. fig. 2.) 



Euchlanis pyriformis Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 200. 



[SP. CH. Outline of lorica constricted in the middle ; ventral gape narrow, widest 

 in front, with shallow walls ; toes narrow, rod-shaped ; lateral horns of incus over- 

 curved. 



The peculiar narrowing of the edge which gives to this species a pear-shaped outline 

 is caused by the edge of the upper plate being curved right under on each side, 

 this edge being formed by two surfaces thinned off to great tenuity, so as practically to 

 become but one layer at some distance from the edge. The under sides then proceed 

 inwards till they nearly meet, when they are bent downwards into shallow walls, just as 

 in E. deflexa, which recede from either to form projecting lateral points at the front ; 

 while behind they merge into a shallow groove and small sinus, at the end of the upper 

 plate. Along this the foot is extruded, which usually has two setae, a prominence and 

 notch, as in the preceding, and two long toes, quite straight, slender, of equal width, 

 except that they are abruptly pointed. The brain and whole internal organization 

 scarcely differ from those just described ; but the four slender horns that stand up from 

 the sides of the incus are curiously bent over outwardly in the form of hooks. The 

 eye is small, as in the preceding. In both species the beauty is much enhanced by a 

 line of minute corrugations, running parallel with, and a little within, the margin of 

 the lorica, like the " milling " around the edge of a new coin. Muscles in much pro- 

 fusion, longitudinal, transverse, and oblique, are to be defined in this very fine species. 



I obtained it first at Battersea Rise, only the day before my discovery of E. deflexa. 

 Few specimens occurred, and it has always been a rarity with me. It swims with 

 swiftness and grace ; is of sprightly manners ; is beautiful and attractive, and being 

 large and brilliantly transparent, is well suited for study. P.H.G.] 



The transverse section (fig. 2a), was obtained by viewing the animal, which I 

 have drawn in fig. 2, directly in front ; it is taken through the turned-in portions of the 

 dorsal plate. It shows that at these spots, the flange of the ventral plate (according to 

 my interpretation of the lorica), almost touches the dorsal edge. These curiously bent 

 portions varied somewhat in different specimens ; but all my examples had four setae on 

 the foot. The hind portion of the nervous ganglion was darker, denser, and more 

 obviously cellular than the fore-part, from which it was separated by a wavy outline. 

 Its front edge was also scalloped like that of E. lyra. 



Length. Up to ^ inch ; of lorica, (; V incn 5 of toes ' TV* mcn - Habitat. Orna- 

 mental waters (P.H.G.) ; garden pond, Clifton (C.T.H.) : rare. 



